Method of making rubber articulated joints



Dec. 28, 1948;

H. M. DODGE 2,457,647

METHOD OF MAKING RUBBER ARTICULATED JOINTS Original Filed Aug. 3, 1942 INVENTOR Howard M. Dodge ATTORNEYS Patented Dec. 28, 1948 UNITED STATES PATENT OFFICE.-

METHOD OF MAKING mum ARTICULATED JOINTS Howard M. Dodge, Wabash, Ind., assignor to The General Tire &

a corporation of Ohio Original application An Rubber Company, Akron, Ohio,

gust 3, 1942, Serial No.

453,355. Divided and this application March 3, 1945, Serial No. 580,878

v 1 Claim. 29-1483) the metal members in a condition of substantial tension throughout the mass thereof.

It has heretofore been proposed to effect connection between two metallic sleeves by slipping a section of heavy walled rubber tubing along a tapered space into the space between inner and outer sleeve members to compress and elongate the rubber into frictional engagement with each of the sleeve members. In assembling rubber members in this manner where surface movement is had between the rubber and the sleeve members, it is almost essential'that a lubricant such as soap be applied to the sliding surface. It has also been found that due to the sliding action of the assembly, strain applied to variousparts of the rubber is not at all uniform and that some joints prepared by sliding assembly fail prematurely.

It is an object of the present invention to provide a rubber articulated joint between two annularly spaced telescoping metal .members in which the rubber or ru-bberlike material is under I relatively uniform compressive stress throughout.

It is another object of the present invention to provide rubber articulated joints between telescoping metallic sleeves in which the entire mass of rubber is under relatively uniform tension due to compression between said sleeves, and in which the side edges of the compressed rubber occupy substantially the position with respect to the mass thereof as they occupied in the undeformed rubber. 1

It is still another object of the present invention to provide a method of making stable rubber articulated joints between telescoping metallic members wherein slipping movements between the surface of the metal members and the surface of the rubber member are substantially eliminated during assembly.

It is another object of the present invention to provide a method of assembling rubber articulated torsional joints between telescoping cylindrical metal sleeves wherein therubber is incorporated between said sleeves without appreciable sliding movement and without the necessity of utilizing a lubricant.

It is a still further object of the present invention to provide a method of assembling rubber 'flexible bearing blocks suitable for use as fixed supports or as joints between relatively movable members having telescoping metallic members joined by rubberlike material pression, wherein the rubberlike material is incorporated between the concentric metallic mem bers with substantial elimination of sliding movement between the surface of the rubber material and themetallic members.

Other objects will be apparent from the following description of the invention asillustrated by the drawing in which:

Figure 1 is an elevational view of a mandrelhaving rubber of cylindrical section wound spirally thereon for curing in open steam, so that rubber rings having a substantially round section may be readily and economically prepared;

Fig. 2 is a sectional view on the line 2-2 of Fig. 1 showing the preferred shape of an extruded strip of rubber for to produce a substantially round section when wound thereon;

Fig. 3 is an elevational view of a modified form of apparatus which may be used in obtaining the deformable rings preferably of the present invention;

Fig. 4 is an elevational view, partly in section,

of a portion of apparatus used in assembling the joints of the present invention, showing the inner and outer sleeves and the annular elastic ring in position for the first step of the assembling process;

Fig. 5 is a similar view showing the position of apparatus and the members of the joint at the end of the assembling operation;

Fig. 6 is an elevational view, with'parts broken away, of a joint member embodying the present invention: and

Fig. 7 is an elevational view, partly in section,

of a portion of a modified form of apparatus, showing in solid lines joint members in position for assembling and in broken lines the Joint in assembled position.

In accordance with the present invention, an

annular deformable elastic member usually of rubber or vulcanized rubberlike material and of substantially round section, preferably having a volume so that the rubber is in Just sufilcient amount to substantially fill the annular space between the inner and outer members of the Joint, is rolled in an inside-out movement by relative longitudinal or telescopic movement of the inner and outer joint members into the desired position. The annular deformable elastic member is rolled through a tapered path of gradually decreasing under high comwinding around the mandrel used in the practice diameter and the inner joint member, which is usually a sleeve, is provided with a removable tipered tip or leader m ber of the desired length to cause the elastic material or rubber member to' make one or more complete revolutions so that in its final position the side edges of the elastic maupon a suitable mandrel 3, which has a spiral groove 4 with a rounded surface, curing the wound strip in a suitable medium, such as in asteam chamber (not shown), separating each turn of cured rubber from the other, and adhering two ends of the separate turns together to form a generally toroidal annulus. Separation of the elasticmemberiwilibepositionedasdelired betweentheinnersleeve l2 endtheoutersleeve 22 when the members i2 and 22 are telacoped in podtion concentric with each other, as hereinafter described;

Theuiiperoriorward endofthe'shelloronter sleeve 22 carries a removable mounting member 22 having a tapered inner opening 2|. The lower portion of the mounting member is bored to receive one end portion or the outer rigid element or sleeve 22. A shoulder 2| of the mounting member23isadaptedtobearupontheupperendot the shell or outer sleeve 22. The-lower inner diameter of the opening 24 adjacent the shoulder 2! is smaller than the diameter of the opening a at the upper edge of the member 22 and preferturns is preferably accomplished by applying a out through each turn longitudinally of the oi the mandrel.

The strip 2 is preferably extruded in an eggshaped or slightly elongated section as illustrated in Fig. 2, so that when the strip is bent and applied to the mandrel it willhave a round cross section.

'The annular elastic member i is preferably of generally toroidal shape with a round or substantially round half cross section. If desired, the member I may be molded in toroidal form in a suitable mold. such for example as illustrated in Fi 3.

The molding apparatus of Fig. 3 comprises a plurality of mold members ii, each having an annular groove of a diameter corresponding to the mean diameter of the elastic members i. The mold members 5 may be assembled on a bolt 6 to form a toroidal cavity by the coaction of the grooves in each pair of mold members 5. Suitable rubber material is placed in the groove of the mold members and pressure applied by tightenin of a nut 1 against a spring 8. The mold apparatus is immersed in a heating medium to cure the rubber therein and produce the annular elastic members i in toroidal shape.

In the preparation of joints embodying the present invention, suitable press having a platen") and a plunger ii optionally movable toward and away from each other and capable of exerting substantial pressure on elements inserted between the platen ill and plunger Ii. The inner member of the Joint may be a cylindrical sleeve i2 andmay be carried on the outer tip it of the plunger Ii. A leader member I4 is preferably applied to the leading'end of the sleeve ii. The leader member it may have a tail portion l6 adapted to fit within the sleeve l2 so that the shoulder it bears against the leading and of the sleeve i2. The leading end of the leader member i4 is provided with a tapered tip ii to facilitate entry of the leader member into the opening i8 of the annular elastic member l. The tip ll of the leader may have a fastening portion which is frictionally held within a bore M 'in' the leading end of the cylindrical body of the leader member ll. Means such as spacing washers it are preferably provided for adjusting the eil'ective length of the cylindrical body of the leader member It so that the annular preciable surface sliding.

ably is substantiaily'equal to the inner diameter 'or the memberffll' The length of the tapered portion of the member 22 may be so chosen that the annular member i will be rotated in the desired position within the member 22 without apannular elastic member i, which is composed of vulcanized rubber or vulcanized rubberlike material such as synthetic rubber. is disposed within a In the assembly of the joint or the mounting member 2: with its outer Surfaceportion bearing against the conical or tapered surface of the inner opening 24. The tip II or the leader member I4 and the inner member of the sleeve i2 are then successively pressed into the central opening of the generally toroidal elastic member I, which is. of substantially round cross section without sharp corners. causing the rubber of the member i to move in a rotatable manner through a tapered path of gradually decreasing cross-sectional area until the desired portion of the sleeve i2 is telescoped into the outer cylindricalsleeve 22. The leader member I and the tip l1 extend into an opening 21 of the plate i0. as shown in Fig. 5. Since the members i2 and 22 are assembled with inside-out use is preferably made of a rotation of the elastic member i. it is seen that sliding between surface portions of the rubberiike material is substantially eliminated. While the annular elastic member is in the joint is under high radial compression, substantially all parts thereof are under identical stress and there is no appreciable stretching of one part with respect to another.

In the modification shown in Fig. 7, the strip 2 of rubberlike material is extruded or molded with a groove or marking 30 of diiferent color than that of the remainder of the material 2. vUse may be made of the marking 30 to adjust the length of the leader member II by adding-or subtracting spacing washers l9 and to also adjust length of the pathalong the mounting member 22 by the number of washers 8|, so that the rubberiike material makes one'or more complete rotations in the assembly of the joint and the exposed edges are under no strain other than that produced by compression or the rubber between the untapered inner and outer sleeve members.

When the joint is assembled as shown in Fig. I, it is seen that the edge portion bears the same relation to the mass or deformable material as it did when vulcanized. The rubberlike material is under stress identical with that obtained by expanding or deforming the diameter of the inner opening it of the annular elastic member to correspond with the outerdiameter of the tube i2, 7

withlout rotating or sliding movement of the member Joints produced in accordance with the present invention have high fatigue resistance. Although the rubberlike material is under high stress, the :Ioints are stable and the inner and outer sleeves do not tend to move longitudinally relative to each other when the assembling pressure is removed.

Since lubricant is not necessary between the rubber or the rubberlike material and the inner and outer elements, slippage of the inner member with respect to the outer member is had, if had at all, only under exceedingly high deformations, and the entire relative movement between the ri id elements is taken up by strain in the rubberlike material. Rubberlike material la preferably does not extend substantially beyond one of the inner or outer sleeves, whichever is shorter.

- have been herein shown and described, it will be understood that other modifications of the construction shown may be resorted to without departing from the spirit of this invention as defined in the appended claim.

What I claim is:

In a method for effecting connection between an inner cylindrical element and a concentric outer cylindrical element of a torsional joint, wherein an annular, deformable, elastic, generally 6 toroidal member of rubberlike material having a substantially round cross section and having a thickness greater than the distance between said inner and outer concentric elements is disposed into a mounting member having an internal bore with a tapered surface ad with is disposed at one end of said outer element, and a leader member having a leading end of smaller diameter than the diameter of the inner element is disposed at the leading end of sai dinner element, and said generally toroidal member is caused to rotate in an inside out manner by relative movement of the leader and inner members with respect to the outer member through a path of decreasing cross sectional area into a cylindrical space between said inner and said outer elements, the steps which comprise regulating the effective length of the leader member and the mounting member so that the deformable member is rotated only so that one side edge of the annular undeformed deformable member is also positioned at the side edge of the deformable member in the deformed state, whereby the side edge is in the unstressed condition of greatest resistance to surface deterioration when exposed to air.

HOWARD M. DODGE.

REFERENCES CITED The following references are of'record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,739,270 Thiry Dec. 10, 1929 2,008,772 Robertson July 23, 1935 2,329,000 Rembert Sept. 7, 1943 2,379,508 Dodge July 3, 1945 

